MODELLING LOCALIZED FRACTURE OF REINFORCED CONCRETE BEAMS UNDER FIRE CONDITIONS

摘要

For performance-based fire safety design, it is important to assess the integrity of reinforced concrete members subjected to localized cracks.At present very little research has been done on the modelling of localized failures of reinforced concrete structural members in fire.To address this, a robust finite element procedure for modelling the localized fracture of reinforced concrete beams at elevated temperatures is developed in this paper.In this model a reinforced concrete beam is represented as an assembly of 4-noded quadrilateral plain concrete, 3-noded main reinforcing steel bar, and 2-noded bond-link elements.The plain concrete element is subdivided into layers for considering the temperature distribution over the cross-section of a beam.An extended finite element method (XFEM) has been incorporated into the plain concrete elements to capture the localized cracks within the plain concrete.The new model has been validated against previous fire test results on the reinforced concrete beams.